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1/*
2 * Definitions for the UDP-Lite (RFC 3828) code.
3 */
4#ifndef _UDPLITE_H
5#define _UDPLITE_H
6
7#include <net/ip6_checksum.h>
8
9/* UDP-Lite socket options */
10#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
11#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
12
13extern struct proto udplite_prot;
14extern struct udp_table udplite_table;
15
16/*
17 * Checksum computation is all in software, hence simpler getfrag.
18 */
19static __inline__ int udplite_getfrag(void *from, char *to, int offset,
20 int len, int odd, struct sk_buff *skb)
21{
22 return memcpy_fromiovecend(to, (struct iovec *) from, offset, len);
23}
24
25/* Designate sk as UDP-Lite socket */
26static inline int udplite_sk_init(struct sock *sk)
27{
28 udp_sk(sk)->pcflag = UDPLITE_BIT;
29 return 0;
30}
31
32/*
33 * Checksumming routines
34 */
35static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
36{
37 u16 cscov;
38
39 /* In UDPv4 a zero checksum means that the transmitter generated no
40 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
41 * with a zero checksum field are illegal. */
42 if (uh->check == 0) {
43 LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: zeroed checksum field\n");
44 return 1;
45 }
46
47 cscov = ntohs(uh->len);
48
49 if (cscov == 0) /* Indicates that full coverage is required. */
50 ;
51 else if (cscov < 8 || cscov > skb->len) {
52 /*
53 * Coverage length violates RFC 3828: log and discard silently.
54 */
55 LIMIT_NETDEBUG(KERN_DEBUG "UDPLITE: bad csum coverage %d/%d\n",
56 cscov, skb->len);
57 return 1;
58
59 } else if (cscov < skb->len) {
60 UDP_SKB_CB(skb)->partial_cov = 1;
61 UDP_SKB_CB(skb)->cscov = cscov;
62 if (skb->ip_summed == CHECKSUM_COMPLETE)
63 skb->ip_summed = CHECKSUM_NONE;
64 }
65
66 return 0;
67}
68
69/* Slow-path computation of checksum. Socket is locked. */
70static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
71{
72 const struct udp_sock *up = udp_sk(skb->sk);
73 int cscov = up->len;
74 __wsum csum = 0;
75
76 if (up->pcflag & UDPLITE_SEND_CC) {
77 /*
78 * Sender has set `partial coverage' option on UDP-Lite socket.
79 * The special case "up->pcslen == 0" signifies full coverage.
80 */
81 if (up->pcslen < up->len) {
82 if (0 < up->pcslen)
83 cscov = up->pcslen;
84 udp_hdr(skb)->len = htons(up->pcslen);
85 }
86 /*
87 * NOTE: Causes for the error case `up->pcslen > up->len':
88 * (i) Application error (will not be penalized).
89 * (ii) Payload too big for send buffer: data is split
90 * into several packets, each with its own header.
91 * In this case (e.g. last segment), coverage may
92 * exceed packet length.
93 * Since packets with coverage length > packet length are
94 * illegal, we fall back to the defaults here.
95 */
96 }
97
98 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
99
100 skb_queue_walk(&sk->sk_write_queue, skb) {
101 const int off = skb_transport_offset(skb);
102 const int len = skb->len - off;
103
104 csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
105
106 if ((cscov -= len) <= 0)
107 break;
108 }
109 return csum;
110}
111
112/* Fast-path computation of checksum. Socket may not be locked. */
113static inline __wsum udplite_csum(struct sk_buff *skb)
114{
115 const struct udp_sock *up = udp_sk(skb->sk);
116 const int off = skb_transport_offset(skb);
117 int len = skb->len - off;
118
119 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
120 if (0 < up->pcslen)
121 len = up->pcslen;
122 udp_hdr(skb)->len = htons(up->pcslen);
123 }
124 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
125
126 return skb_checksum(skb, off, len, 0);
127}
128
129extern void udplite4_register(void);
130extern int udplite_get_port(struct sock *sk, unsigned short snum,
131 int (*scmp)(const struct sock *, const struct sock *));
132#endif /* _UDPLITE_H */
1/*
2 * Definitions for the UDP-Lite (RFC 3828) code.
3 */
4#ifndef _UDPLITE_H
5#define _UDPLITE_H
6
7#include <net/ip6_checksum.h>
8
9/* UDP-Lite socket options */
10#define UDPLITE_SEND_CSCOV 10 /* sender partial coverage (as sent) */
11#define UDPLITE_RECV_CSCOV 11 /* receiver partial coverage (threshold ) */
12
13extern struct proto udplite_prot;
14extern struct udp_table udplite_table;
15
16/*
17 * Checksum computation is all in software, hence simpler getfrag.
18 */
19static __inline__ int udplite_getfrag(void *from, char *to, int offset,
20 int len, int odd, struct sk_buff *skb)
21{
22 struct msghdr *msg = from;
23 return copy_from_iter_full(to, len, &msg->msg_iter) ? 0 : -EFAULT;
24}
25
26/* Designate sk as UDP-Lite socket */
27static inline int udplite_sk_init(struct sock *sk)
28{
29 udp_sk(sk)->pcflag = UDPLITE_BIT;
30 sk->sk_destruct = udp_destruct_sock;
31 return 0;
32}
33
34/*
35 * Checksumming routines
36 */
37static inline int udplite_checksum_init(struct sk_buff *skb, struct udphdr *uh)
38{
39 u16 cscov;
40
41 /* In UDPv4 a zero checksum means that the transmitter generated no
42 * checksum. UDP-Lite (like IPv6) mandates checksums, hence packets
43 * with a zero checksum field are illegal. */
44 if (uh->check == 0) {
45 net_dbg_ratelimited("UDPLite: zeroed checksum field\n");
46 return 1;
47 }
48
49 cscov = ntohs(uh->len);
50
51 if (cscov == 0) /* Indicates that full coverage is required. */
52 ;
53 else if (cscov < 8 || cscov > skb->len) {
54 /*
55 * Coverage length violates RFC 3828: log and discard silently.
56 */
57 net_dbg_ratelimited("UDPLite: bad csum coverage %d/%d\n",
58 cscov, skb->len);
59 return 1;
60
61 } else if (cscov < skb->len) {
62 UDP_SKB_CB(skb)->partial_cov = 1;
63 UDP_SKB_CB(skb)->cscov = cscov;
64 if (skb->ip_summed == CHECKSUM_COMPLETE)
65 skb->ip_summed = CHECKSUM_NONE;
66 }
67
68 return 0;
69}
70
71/* Slow-path computation of checksum. Socket is locked. */
72static inline __wsum udplite_csum_outgoing(struct sock *sk, struct sk_buff *skb)
73{
74 const struct udp_sock *up = udp_sk(skb->sk);
75 int cscov = up->len;
76 __wsum csum = 0;
77
78 if (up->pcflag & UDPLITE_SEND_CC) {
79 /*
80 * Sender has set `partial coverage' option on UDP-Lite socket.
81 * The special case "up->pcslen == 0" signifies full coverage.
82 */
83 if (up->pcslen < up->len) {
84 if (0 < up->pcslen)
85 cscov = up->pcslen;
86 udp_hdr(skb)->len = htons(up->pcslen);
87 }
88 /*
89 * NOTE: Causes for the error case `up->pcslen > up->len':
90 * (i) Application error (will not be penalized).
91 * (ii) Payload too big for send buffer: data is split
92 * into several packets, each with its own header.
93 * In this case (e.g. last segment), coverage may
94 * exceed packet length.
95 * Since packets with coverage length > packet length are
96 * illegal, we fall back to the defaults here.
97 */
98 }
99
100 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
101
102 skb_queue_walk(&sk->sk_write_queue, skb) {
103 const int off = skb_transport_offset(skb);
104 const int len = skb->len - off;
105
106 csum = skb_checksum(skb, off, (cscov > len)? len : cscov, csum);
107
108 if ((cscov -= len) <= 0)
109 break;
110 }
111 return csum;
112}
113
114/* Fast-path computation of checksum. Socket may not be locked. */
115static inline __wsum udplite_csum(struct sk_buff *skb)
116{
117 const struct udp_sock *up = udp_sk(skb->sk);
118 const int off = skb_transport_offset(skb);
119 int len = skb->len - off;
120
121 if ((up->pcflag & UDPLITE_SEND_CC) && up->pcslen < len) {
122 if (0 < up->pcslen)
123 len = up->pcslen;
124 udp_hdr(skb)->len = htons(up->pcslen);
125 }
126 skb->ip_summed = CHECKSUM_NONE; /* no HW support for checksumming */
127
128 return skb_checksum(skb, off, len, 0);
129}
130
131void udplite4_register(void);
132int udplite_get_port(struct sock *sk, unsigned short snum,
133 int (*scmp)(const struct sock *, const struct sock *));
134#endif /* _UDPLITE_H */